The Cycliophora are a new phylum, based on a single genus Symbion. They are so different from other animals that they were put in their own phylum. They were discovered in 1995, and are the most recent new phylum. So far, three species have been found.
They live on the bodies of cold-water lobsters. They are microscopic: the feeding stage is about 0.3 mm long, and 0.1 mm wide.